the highwaystars cable is slip on for OE speedometers not for SW/vdo mechanical speedos
search ebay they are listed as VDO speedometer cable , 38" will work if using the factory lower cable
Find many great new & used options and get the best deals for PRO STREET ROD RAT ROD HOT ROD SPEEDOMETER CABLE FITS AUTOMETER EQUUS VDO GAUGE at the best online prices at eBay! Free shipping for many products!
www.ebay.com
napa may also have something like it